Covid-19: how effective is the bivalent vaccine booster?

From April, people over 30 will be able to get a Covid booster which includes protection against the Omicron variant. A total 1.7 million doses of the new "bivalent" vaccines will arrive in New Zealand over the next few months. In Australia, things are a little bit more advanced and from next week Australian adults will be able to get a bivalent booster. To get an idea how the rollout is going in Australia and why it's important, Nathan Rarere spoke to the Chair of Epidemiology at Victoria's Deakin University, professor Catherine Bennett. He asked how much extra protection this booster shot offers.